Adult T-cell leukaemia/lymphoma with different histological features in a single lymph node

We report a case of adult T-cell leukaemia/lymphoma (ATLL) that exhibited different pathological subtypes within a single lymph node. The patient was a 76-year-old Japanese man who presented with decreased appetite and anemia, and a thorough examination was conducted. A peripheral blood analysis and imaging studies, including ultrasound and computed tomography, suggested malignant lymphoma, and cervical lymph node biopsy was subsequently performed.In the excised lymph node, the normal architecture was completely effaced, and areas showing the dense proliferation of pleomorphic atypical lymphocytes-consistent with the most common histology of ATLL (pleomorphic cell variant)-were identified. Regions exhibiting features reminiscent of classic Hodgkin lymphoma and others resembling angioimmunoblastic T-cell lymphoma were also observed. Serological testing was positive for human T-lymphotropic virus type 1 antibodies, and together with histological findings, this case was diagnosed as ATLL.To the best of our knowledge, there have been no cases exhibiting different histological patterns within a single lymph node.